Turkey's Servet Tazegul won gold in the men's -68kg competition, but Great Britain's Martin Stamper missed out on a bronze medal.
Tazegul, the 2011 world champion, beat Mohammad Motamed of Iran 6-5 to clinch the title.
Stamper lost 5-3 to Afghanistan's Rohullah Nikpah - a three-point head kick proving the difference.
"It is tough to take because I have worked so hard over the past two years," said Stamper.
Stamper was beaten by top seed and eventual gold medallist Tazegul in the semi-finals, meaning he was given a second chance in the repechage.
"I knew if I put in four good performances, I could achieve anything and I was so close in the semi-final to pulling off a shock," he said.
"In the bronze match, I just made one mistake when I thought I was controlling the match, then one head shot changed the game."
In the final, Tazegul had too much class for Motamed, thanks to his aggressive combinations of spinning and jumping kicks.
"This is the first gold medal for Turkey in these Olympics and I'm happy that I was the one who earned it," said Tazegul.
American Terrence Jennings won the first bronze, beating Brazilian Diogo Silva 8-5.